The invention relates to plastic piping. More particularly, the invention relates to preparation of plastic pipe/tube material for electro-fusion bonding.
In order to connect thermoplastic piping systems together via electro-fusion methods it is standard practice to remove the outer oxidized surface of the pipe to expose clean un-contaminated plastic. Previous methods rely on fixed or pivoting cutting tools and/or internal drive mandrels to remove the outer oxidized layers.
An exemplary fixed diameter tool does not adequately scrape pipe that has an oval shape due to coiling.
An exemplary pivoting tool scraper relies on an internal drive mandrel to limit the forward helical cutting motion. On occasion it is necessary to connect two different thicknesses of pipe wall. This would require use of two different internal drive scrapers.
Examples of prior tools include those shown in U.S. Pat. Nos. 5,600,862, 6,434,776, and 6,698,321 and US patent application publication 2011232434A1. One additional previously proposed alternative features two spring-loaded scraping blades mounted in a generally tubular body.